2 protocol_key.c -- handle the meta-protocol, key exchange
3 Copyright (C) 1999-2005 Ivo Timmermans,
4 2000-2012 Guus Sliepen <guus@tinc-vpn.org>
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License along
17 with this program; if not, write to the Free Software Foundation, Inc.,
18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23 #include "splay_tree.h"
25 #include "connection.h"
37 static bool mykeyused = false;
39 void send_key_changed(void) {
43 send_request(everyone, "%d %x %s", KEY_CHANGED, rand(), myself->name);
45 /* Immediately send new keys to directly connected nodes to keep UDP mappings alive */
47 for(node = connection_tree->head; node; node = node->next) {
49 if(c->status.active && c->node && c->node->status.reachable) {
50 if(!c->node->status.sptps)
51 send_ans_key(c->node);
55 /* Force key exchange for connections using SPTPS */
58 for(node = node_tree->head; node; node = node->next) {
59 node_t *n = node->data;
60 if(n->status.reachable && n->status.validkey && n->status.sptps)
61 sptps_force_kex(&n->sptps);
66 bool key_changed_h(connection_t *c, const char *request) {
67 char name[MAX_STRING_SIZE];
70 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
71 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
72 c->name, c->hostname);
76 if(seen_request(request))
79 n = lookup_node(name);
82 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
83 "KEY_CHANGED", c->name, c->hostname, name);
87 if(!n->status.sptps) {
88 n->status.validkey = false;
95 forward_request(c, request);
100 static bool send_initial_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
102 to->sptps.send_data = send_sptps_data;
103 char buf[len * 4 / 3 + 5];
104 b64encode(data, buf, len);
105 return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_KEY, buf);
108 bool send_req_key(node_t *to) {
109 if(to->status.sptps) {
110 if(!node_read_ecdsa_public_key(to)) {
111 logger(DEBUG_ALWAYS, LOG_DEBUG, "No ECDSA key known for %s (%s)", to->name, to->hostname);
112 send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, REQ_PUBKEY);
115 char label[25 + strlen(myself->name) + strlen(to->name)];
116 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", myself->name, to->name);
117 return sptps_start(&to->sptps, to, true, true, myself->connection->ecdsa, to->ecdsa, label, sizeof label, send_initial_sptps_data, receive_sptps_record);
120 return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
123 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
125 static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, int reqno) {
128 char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
129 send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
135 if(node_read_ecdsa_public_key(from)) {
136 logger(DEBUG_ALWAYS, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
140 char pubkey[MAX_STRING_SIZE];
141 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !ecdsa_set_base64_public_key(&from->ecdsa, pubkey)) {
142 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
146 logger(DEBUG_ALWAYS, LOG_INFO, "Learned ECDSA public key from %s (%s)", from->name, from->hostname);
147 append_config_file(from->name, "ECDSAPublicKey", pubkey);
152 if(!node_read_ecdsa_public_key(from)) {
153 logger(DEBUG_ALWAYS, LOG_DEBUG, "No ECDSA key known for %s (%s)", from->name, from->hostname);
154 send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
160 char buf[MAX_STRING_SIZE];
161 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1) {
162 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", from->name, from->hostname, "invalid SPTPS data");
165 int len = b64decode(buf, buf, strlen(buf));
168 char label[25 + strlen(from->name) + strlen(myself->name)];
169 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name);
170 sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data, receive_sptps_record);
171 sptps_receive_data(&from->sptps, buf, len);
176 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
181 bool req_key_h(connection_t *c, const char *request) {
182 char from_name[MAX_STRING_SIZE];
183 char to_name[MAX_STRING_SIZE];
187 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
188 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
193 if(!check_id(from_name) || !check_id(to_name)) {
194 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
198 from = lookup_node(from_name);
201 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
202 "REQ_KEY", c->name, c->hostname, from_name);
206 to = lookup_node(to_name);
209 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
210 "REQ_KEY", c->name, c->hostname, to_name);
214 /* Check if this key request is for us */
216 if(to == myself) { /* Yes */
217 /* Is this an extended REQ_KEY message? */
218 if(experimental && reqno)
219 return req_key_ext_h(c, request, from, reqno);
221 /* No, just send our key back */
227 if(!to->status.reachable) {
228 logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
229 "REQ_KEY", c->name, c->hostname, to_name);
233 send_request(to->nexthop->connection, "%s", request);
239 bool send_ans_key(node_t *to) {
243 size_t keylen = cipher_keylength(&myself->incipher);
244 char key[keylen * 2 + 1];
246 cipher_open_by_nid(&to->incipher, cipher_get_nid(&myself->incipher));
247 digest_open_by_nid(&to->indigest, digest_get_nid(&myself->indigest), digest_length(&myself->indigest));
248 to->incompression = myself->incompression;
250 randomize(key, keylen);
251 cipher_set_key(&to->incipher, key, false);
252 digest_set_key(&to->indigest, key, keylen);
254 bin2hex(key, key, keylen);
256 // Reset sequence number and late packet window
258 to->received_seqno = 0;
259 if(replaywin) memset(to->late, 0, replaywin);
261 return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
262 myself->name, to->name, key,
263 cipher_get_nid(&to->incipher),
264 digest_get_nid(&to->indigest),
265 (int)digest_length(&to->indigest),
269 bool ans_key_h(connection_t *c, const char *request) {
270 char from_name[MAX_STRING_SIZE];
271 char to_name[MAX_STRING_SIZE];
272 char key[MAX_STRING_SIZE];
273 char address[MAX_STRING_SIZE] = "";
274 char port[MAX_STRING_SIZE] = "";
275 int cipher, digest, maclength, compression, keylen;
278 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
279 from_name, to_name, key, &cipher, &digest, &maclength,
280 &compression, address, port) < 7) {
281 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
286 if(!check_id(from_name) || !check_id(to_name)) {
287 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
291 from = lookup_node(from_name);
294 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
295 "ANS_KEY", c->name, c->hostname, from_name);
299 to = lookup_node(to_name);
302 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
303 "ANS_KEY", c->name, c->hostname, to_name);
307 /* Forward it if necessary */
313 if(!to->status.reachable) {
314 logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
315 "ANS_KEY", c->name, c->hostname, to_name);
319 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
320 char *address, *port;
321 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
322 sockaddr2str(&from->address, &address, &port);
323 send_request(to->nexthop->connection, "%s %s %s", request, address, port);
329 return send_request(to->nexthop->connection, "%s", request);
332 /* SPTPS or old-style key exchange? */
334 if(from->status.sptps) {
335 char buf[strlen(key)];
336 int len = b64decode(key, buf, strlen(key));
338 if(!sptps_receive_data(&from->sptps, buf, len))
339 logger(DEBUG_ALWAYS, LOG_ERR, "Error processing SPTPS data from %s (%s)", from->name, from->hostname);
341 if(from->status.validkey) {
342 if(*address && *port) {
343 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
344 sockaddr_t sa = str2sockaddr(address, port);
345 update_node_udp(from, &sa);
348 if(from->options & OPTION_PMTU_DISCOVERY)
349 send_mtu_probe(from);
355 /* Check and lookup cipher and digest algorithms */
357 if(!cipher_open_by_nid(&from->outcipher, cipher)) {
358 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
362 if(!digest_open_by_nid(&from->outdigest, digest, maclength)) {
363 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
367 if(maclength != digest_length(&from->outdigest)) {
368 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
372 if(compression < 0 || compression > 11) {
373 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
377 from->outcompression = compression;
381 keylen = hex2bin(key, key, sizeof key);
383 if(keylen != cipher_keylength(&from->outcipher)) {
384 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
388 /* Update our copy of the origin's packet key */
390 cipher_set_key(&from->outcipher, key, true);
391 digest_set_key(&from->outdigest, key, keylen);
393 from->status.validkey = true;
394 from->sent_seqno = 0;
396 if(*address && *port) {
397 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
398 sockaddr_t sa = str2sockaddr(address, port);
399 update_node_udp(from, &sa);
402 if(from->options & OPTION_PMTU_DISCOVERY)
403 send_mtu_probe(from);